CN104257382A - Electromagnetic wave propagation speed based biological tissue electromagnetic parameter imaging device and method - Google Patents

Abstract

The invention discloses an electromagnetic wave propagation speed based biological tissue electromagnetic parameter imaging device and method and belongs to the field of biological tissue electromagnetic parameter imaging. The electromagnetic wave propagation speed based biological tissue electromagnetic parameter imaging device comprises an electromagnetic wave transmitting coil, an electromagnetic wave receiving coil, a U-shaped arm, an objective table, a motor unit, a motor driving unit, a control unit and an opening type oscillating circuit. The electromagnetic wave propagation speed based biological tissue electromagnetic parameter imaging method comprises initializing devices; measuring the electromagnetic wave propagation speed of biological tissues; enabling an FPGA (Field Programmable Gate Array) to upload the electromagnetic wave propagation time to a terminal computer in real time through a single chip microcomputer, enabling the terminal computer to calculate the electromagnetic wave propagation speed of positions of the biological tissues through a speed formula according to the distance between the electromagnetic wave transmitting coil and the electromagnetic wave receiving coil; performing image reconstruction on the biological tissue through a regularization Gaussian Newton reconstruction algorithm (NOSER) and obtaining a reconstruction image of the biological tissue. The electromagnetic wave propagation speed based biological tissue electromagnetic parameter imaging device and method provides a brand new, simple and effective detection mean and is low in cost and free of radiation compared with traditional medical imaging equipment.

Description

Based on biological tissue's electromagnetic parameter imaging device and the method for propagation velocity of electromagnetic wave

Technical field

The invention belongs to biological tissue's electromagnetic parameter imaging field, particularly relate to the biological tissue's electromagnetic parameter imaging device based on propagation velocity of electromagnetic wave and method.

Background technology

Biological tissue is made up of cell, and cell is made up of intracellular fluid, extracellular fluid and cell membrane, and the external environment residing for it is extracellular fluid.The electromagnetic property of biological tissue, be phalangeal cell passive under the effect of electromagnetic field generation polarization reaction dielectric response characteristic.Particularity due to mechanics of biological tissue makes its electromagnetic property also be not quite similar, and the electromagnetic property of biological tissue has the passive characteristic of frequency dependent.There is the relaxation of three kinds of frequency bands α, β, γ in biological tissue, and electromagnetic property has significant change within the scope of three band frequencies.When the electromagnetic field effect of different frequencies, varying strength is in biological tissue, different electromagnetic propertys can be shown.The electromagnetic property of some pathological tissues and normal structure has larger difference.Under different physiology, pathological state, there is different electromagnetic propertys according to different tissues in organism, surveyed organization type can be judged by measuring biological tissue's electromagnetic property signal, the growing state of cell and the pathological changes situation of tissue can be inferred according to electromagnetic property further.

The detection of biological tissue's electromagnetic property needs harmless detection mode.Current electric impedance detection method is faced with the not high problem of imaging resolution, and the factor affecting resolution is not single, no matter be measuring method or formation method, or both inharmonious all can have impact to imaging results.And current magnetic induction image detection method carries out a kind of noinvasive of image reconstruction, harmless, new technique without the need to directly contacting with testee to Suo Ce biological tissue electromagnetic parameter, although people to its research for many years, but the raising of its secondary magnetic field certainty of measurement and imaging resolution is difficult, distance widely uses or there is a big difference.The electromagnetic parameter such as dielectric constant and pcrmeability of the spread speed of electromagnetic wave in biological tissue and biological tissue has certain corresponding relation, and had scholar to be applied in engineering geologic investigation by propagation velocity of electromagnetic wave, the auxiliary accuracy improving detection solution cavity and filling situation thereof.But because the size of biological tissue is less, the time that electromagnetic field is propagated in biological tissues is very short, and the order of magnitude reaches nanosecond, is difficult to its propagation time of Measurement accuracy by conventional method.

Summary of the invention

For the deficiency that prior art exists, the invention provides a kind of biological tissue's electromagnetic parameter imaging device based on propagation velocity of electromagnetic wave and method.

Technical scheme of the present invention:

Based on biological tissue's electromagnetic parameter imaging device of propagation velocity of electromagnetic wave, comprising: electromagnetic radiation coil, electromagnetic wave receiving coil, U-shaped arm, object stage, electric motor units, electric-motor drive unit, control unit and open oscillating circuit;

Described control unit is formed primarily of FPGA, single-chip microcomputer and terminal computer; Described single-chip microcomputer and FPGA interconnect, and single-chip microcomputer also interconnects with terminal computer simultaneously;

Described open oscillating circuit is used for accumulating the time that electromagnetic wave is propagated in biological tissues by repeatedly vibrating, and it comprises: monostable trigger control circuit, pumping signal radiating circuit, signal conditioning circuit, AGC-shaping circuit, delay circuit and timing circuit;

Described monostable trigger control circuit and FPGA interconnect, an input of monostable trigger control circuit connects an outfan of delay circuit simultaneously, an outfan of monostable trigger control circuit connects the input of pumping signal radiating circuit, and another outfan of monostable trigger control circuit connects an input of timing circuit; The outfan of described pumping signal radiating circuit connects electromagnetic radiation coil, and pumping signal radiating circuit connects FPGA by data/address bus simultaneously, the data that unidirectional reception FPGA sends; Another input of described timing circuit connects another outfan of delay circuit, and timing circuit also interconnects with FPGA simultaneously; The input of described delay circuit connects the outfan of AGC-shaping circuit; The outfan of the input connection signal modulate circuit of described AGC-shaping circuit; The input of described signal conditioning circuit connects electromagnetic wave receiving coil;

Described electromagnetic radiation coil is used under the driving of pumping signal radiating circuit, produce the electromagnetic wave that can pass biological tissue;

Described electromagnetic wave receiving coil is for receiving the electromagnetic wave through biological tissue;

Described electromagnetic radiation coil, electromagnetic wave receiving coil are separately fixed in the two-arm of U-shaped arm, and the relative position of two coils immobilizes, and the axis of electromagnetic radiation coil and electromagnetic wave receiving coil in the same horizontal line;

Described object stage is cylinder, and on it, end face is for placing biological tissue to be measured, is placed in the inner chamber of U-shaped arm, and and leave corresponding gap between the two-arm of U-shaped arm; When described object stage is placed in the inner chamber of U-shaped arm, the gap between itself and the two-arm of U-shaped arm does not affect object stage with U-shaped arm and rotates as principle adjusts.

Described electric motor units is for driving U-shaped arm to carry out translational motion and object stage is rotated, and it comprises: translation motor carries out translational motion for driving U-shaped arm; Rotating stepper motor is used for driving objective table and is rotated;

Described electric-motor drive unit is used for the operation of motor in drive motor units, and it comprises: translation stepper motor driving circuit is the drive circuit of described translation motor, for driving the translation operation of translation motor; Rotating stepper motor drive circuit is the drive circuit of described rotating stepper motor, for driving the rotating operation of rotating stepper motor;

U-shaped arm is connected with the output shaft end of translation motor, the power access end of described translation motor connects the outfan of translation stepper motor driving circuit, the input of described translation stepper motor driving circuit connects FPGA by control bus, receives the control command signal that FPGA sends;

Described object stage is connected with rotating stepper motor output shaft end; The power access end of described rotating stepper motor connects the outfan of rotating stepper motor drive circuit, and the input of described rotating stepper motor drive circuit connects FPGA by control bus, receives the control command signal that FPGA sends;

Described object stage and U-shaped arm all by leading screw respectively the output shaft end that move motor peaceful to the output shaft end of rotating stepper motor be connected;

The thick iron sheet of 0.5mm is finally adopted to make closed screening can, biological tissue to be measured, object stage, rotating stepper motor, U-shaped arm, electromagnetic radiation coil, the peaceful motor that moves of electromagnetic wave receiving coil are included in wherein by this screening can, carry out electromagnetic shielding to them;

Also being provided with biological tissue's electromagnetic parameter image reconstruction module in described terminal computer, for carrying out image reconstruction to biological tissue, obtaining the reconstruction image of biological tissue.

Biological tissue's electromagnetic parameter formation method of the biological tissue's electromagnetic parameter imaging device based on propagation velocity of electromagnetic wave described in employing, comprises the steps:

Step 1: device initializes;

Step 1.1: send initialization directive from terminal computer, and send this instruction to FPGA by single-chip microcomputer;

Step 1.2: after receiving initialization directive, FPGA controls pumping signal radiating circuit, monostable trigger control circuit, timing circuit and delay circuit and completes initial work;

Step 1.2.1:FPGA transmits control signal to pumping signal radiating circuit, the signal tranmitting frequency of setting pumping signal radiating circuit;

Step 1.2.2:FPGA sends reset signal to monostable trigger control circuit, and monostable trigger control circuit is resetted;

Step 1.2.3:FPGA transmits control signal to timing circuit, first makes timing circuit reset, and then arranges the output clock frequency of timing circuit;

Step 1.2.4:FPGA transmits control signal to delay circuit, arranges the delay time of delay circuit;

Step 2: the electromagnetic wave propagation measure of time of biological tissue;

Step 2.1: at initial position, namely object stage rotates, and U-shaped arm does not carry out translation, carries out the measurement of the electromagnetic wave propagation time of biological tissue;

Step 2.1.1: terminal computer sends and starts measurement instruction and send this instruction to FPGA by single-chip microcomputer;

Step 2.1.2:FPGA sends one and starts the pulse signal of measurement and be sent to monostable trigger control circuit;

Step 2.1.3: monostable trigger control circuit is triggered after receiving pulse signal, produces three road pulse signals; Wherein a road pulse signal is sent to the high speed counting module in FPGA, for recording impulse number of times; Another road pulse signal sends to timing circuit, starts timing for controlling timing circuit; 3rd road pulse signal sends to pumping signal radiating circuit;

Step 2.1.4: after receiving pulse signal, pumping signal radiating circuit drives electromagnetic radiation coil generating electromagnetic ripple; This electromagnetic wave is through biological tissue, and after being received by electromagnetic wave receiving coil, electromagnetic wave receiving coil output detections signal is to signal conditioning circuit;

Step 2.1.5: signal conditioning circuit is sent to AGC-shaping circuit after carrying out filter amplifying processing to detection signal;

Step 2.1.6:AGC-shaping circuit carries out automatic range-adjusting to the detection signal received and is sent to delay circuit after being shaped as rectangular pulse signal;

Step 2.1.7: after delay circuit receives rectangular pulse signal, the time delayed signal of generation imports timing circuit and monostable trigger control circuit into simultaneously;

Step 2.1.8: after receiving time delayed signal, timing circuit stops timing, and single-shot trigger circuit is triggered again simultaneously;

Step 2.1.9: repeated execution of steps 2.1.3 to 2.1.8, until after the count value of FPGA high speed counting module reaches the maximum count value of in advance setting, FPGA sends reset enable signal monostable trigger control circuit and resets, and namely open oscillating circuit stops oscillation;

Step 2.1.10: the time value that timer when stopping oscillation according to maximum count value and open oscillating circuit provides, FPGA calculate the electromagnetic wave propagation time of biological tissue, are designated as D ₀₀;

The computational methods of electromagnetic wave propagation time are the maximum count value of time value divided by correspondence of timer transmission;

Step 2.2: keep object stage motionless, the translational motion of U-shaped arm, measure the electromagnetic wave propagation time of biological tissue;

FPGA drives the running of translation motor by translation motor drive circuit, and U-shaped arm is moved horizontally according to pre-determined step-length; U-shaped arm records the electromagnetic wave propagation time of biological tissue after often moving to a new position according to step 2.1.1 to step 2.1.10; After U-shaped arm moves n time, record the electromagnetic wave propagation time data of one group of biological tissue, be designated as D respectively ₀₁, D ₀₂..., D _0n;

Step 2.3: object stage rotates, and the translation of U-shaped arm, measure the electromagnetic wave propagation time of biological tissue;

FPGA drives rotating stepper motor to rotate by electric rotating machine drive circuit, object stage is rotated according to pre-determined step-length, after object stage often rotates to a new position, repeated execution of steps 2.1 to step 2.2, records the electromagnetic wave propagation time data once rotating motionless and U-shaped arm n the movement of corresponding U-shaped arm of object stage; Then after object stage often rotates to a new position, by repeated execution of steps 2.1 to step 2.2, all obtain one group of data, then object stage by motionless to completing 360 degree of rotations, number of revolutions is m, and the data set of the electromagnetic wave propagation time of the biological tissue obtained is:

$D=\left[\begin{array}{ccccc}{D}_{00}& D_{01}& D_{02}& ...& D_{0n}\\ D_{10}& D_{11}& D_{12}& ...& D_{1n}\\ D_{20}& D_{21}& D_{22}& ...& D_{2n}\\ ...& ...& ...& ...& ...\\ D_{m0}& D_{m1}& D_{m2}& ...& D_{\mathrm{mn}}\end{array}\right]$

The data of above-mentioned data centralization are uploaded to terminal computer by single-chip microcomputer by step 3:FPGA in real time one by one, terminal computer is according to the distance between electromagnetic radiation coil and electromagnetic wave receiving coil, and the propagation velocity of electromagnetic wave data set utilizing speed formula to calculate each position of biological tissue corresponding to above-mentioned data is:

$V=\left[\begin{array}{ccccc}{V}_{00}& V_{01}& V_{02}& ...& V_{0n}\\ V_{10}& V_{11}& V_{12}& ...& V_{1n}\\ V_{20}& V_{21}& V_{22}& ...& V_{2n}\\ ...& ...& ...& ...& ...\\ V_{m0}& V_{m1}& V_{m2}& ...& V_{\mathrm{mn}}\end{array}\right]$

Step 4: the data set V utilizing step 3 to obtain, adopts regularization Gauss-Newton algorithm for reconstructing (NOSER) to carry out image reconstruction to biological tissue, obtains the reconstruction image of biological tissue.

Operation principle of the present invention is: apply electromagnetic wave to biological tissue in a non contact fashion, by measuring electromagnetic wave propagation time in biological tissue, calculates the speed that electromagnetic wave is propagated in biological tissues.The time that electromagnetic wave is propagated in biological tissue is very short, by adopting open oscillating circuit the small time constantly to be accumulated through repeatedly repeatedly vibrating, then can the propagation time of accurate Calculation electromagnetic wave in biological tissue according to the number of oscillation.According to the distance between electromagnetic radiation coil and electromagnetic wave receiving coil, speed formula is utilized to calculate the propagation velocity of electromagnetic wave of each position of biological tissue; According to the propagation velocity of electromagnetic wave of each position of biological tissue, adopt regularization Gauss-Newton algorithm for reconstructing (NOSER) to carry out image reconstruction to biological tissue, obtain the reconstruction image of biological tissue.

Beneficial effect: the biological tissue's electromagnetic parameter imaging device based on propagation velocity of electromagnetic wave of the present invention and method compared with prior art have following advantage: the present invention proposes the method for a kind of measurement electromagnetic wave completely newly spread speed in biological tissues, for medical research with clinically provide a kind of completely newly, easy, effective detection means; Have with low cost compared to traditional medical imaging devices (as CT, MRI etc.), radiationless feature; Different biological tissue or the electrical conductivity of identical biological tissue under different conditions are different, electromagnetic wave propagation speed is also just different, so adopt method of the present invention build the anatomic information that image not only can provide biological tissue, the physiological status of biological tissue can also be reflected, there is important medical value.

Accompanying drawing explanation

Fig. 1 is the structural representation of the measuring device of biological tissue's propagation velocity of electromagnetic wave of one embodiment of the present invention;

Fig. 2 is the pumping signal radiating circuit schematic diagram of one embodiment of the present invention;

Fig. 3 is the signal conditioning circuit schematic diagram of one embodiment of the present invention;

Fig. 4 is the AGC-shaping circuit schematic diagram of one embodiment of the present invention;

Fig. 5 is the delay circuit schematic diagram of one embodiment of the present invention;

Fig. 6 is the monostable trigger control circuit schematic diagram of one embodiment of the present invention;

Fig. 7 is the timing circuit schematic diagram of one embodiment of the present invention;

The mechanical part top view of the measuring device of biological tissue's propagation velocity of electromagnetic wave that Fig. 8 (a) is one embodiment of the present invention; B () is the side view of figure (a);

Fig. 9 is the motor driving principle figure of one embodiment of the present invention;

Figure 10 is the measuring method flow chart of biological tissue's propagation velocity of electromagnetic wave of one embodiment of the present invention;

Figure 11 is the tomoscan mode schematic diagram of one embodiment of the present invention;

Figure 12 is that the biological tissue of one embodiment of the present invention rebuilds image.

Wherein, the 1. electromagnetic radiation coil 2. electromagnetic wave receiving coil 3.U arc 4. object stage 5. electric motor units 5-1. rotating stepper motor 5-2. parallel motor 6. electric-motor drive unit 6-1. rotating stepper motor drive circuit 6-2. parallel stepper motor driving circuit 7. control unit 7-1.FPGA7-2. single-chip microcomputer 7-3. open oscillating circuit 8-1. pumping signal radiating circuit 8-2. monostable trigger control circuit 8-3. timing circuit 8-4. delay circuit 8-5.AGC-shaping circuit 8-6. signal conditioning circuit 9. of terminal computer 8. biological tissue 10. to be measured screening can 11. first leading screw 12. second leading screw 13. coil fixed support.

Detailed description of the invention

Electromagnetic wave can penetrate organism surface and portion propagates in vivo.From wave theory, when ripple is propagated in biological tissues, its propagation law and ripple wavelength is in biological tissues closely related, and in the air along with wave energy is decayed by the absorption of medium.Usually, if when wavelength is much larger than biological tissue's size, then ripple can be approximately quasistatic physically.

When electromagnetic wave is propagated in biological tissue, the electromagnetic property of its wavelength and each tissue has much relations.Relevant electromagnetic parameter mainly contains: electrical conductivity, dielectric constant and pcrmeability.Wherein in biological tissue's pcrmeability and vacuum, pcrmeability is very close, does not have imaging and is worth.And electrical conductivity and dielectric constant all have larger dependence with wave frequency.The electrical conductivity of different biological tissue and the diversity of dielectric constant as shown in table 1.

Relative dielectric constant, the conductivity value of different biological tissue under table 1 frequency 50MHz

In addition, at inside of human body also containing air, because air is almost insulator, therefore its electrical characteristics and biological tissue have different significantly.For low frequency electromagnetic field, the electromagnetic field entering human body is main as an electrical current, and the electrical characteristics difference with each site tissue redistributes, the region that general selection electrical impedance is little by electric current.For electromagnetic field of high frequency, because it has wave characteristic significantly, its power transfer, decay, reflection and absorption etc. depend primarily on ripple complex transmission coefficient in the tissue and characteristic impedance.

One embodiment of the present invention provide the structured flowchart of the biological tissue's electromagnetic parameter imaging device based on propagation velocity of electromagnetic wave, as shown in Figure 1, comprising: electromagnetic radiation coil 1, electromagnetic wave receiving coil 2, U-shaped arm 3, object stage 4, electric motor units 5, electric-motor drive unit 6, control unit 7, open oscillating circuit 8 and biological tissue's electromagnetic parameter image reconstruction module;

Control unit 7 is formed primarily of FPGA7-1, single-chip microcomputer 7-2 and terminal computer 7-3; In present embodiment, FPGA is the control axis of whole device, completes the control of related hardware, employing be Altera Cyclone EP2C8Q208C8N chip; What single-chip microcomputer adopted is with the model of USB (USB (universal serial bus)) function control device is the single-chip microcomputer of C8051F340, it mainly completes the exchanges data between EP2C8Q208C8N type FPGA and terminal computer, comprise various operational order that terminal computer assigns EP2C8Q208C8N type FPGA and EP2C8Q208C8N type FPGA returns to the hardware state of terminal computer for information about, the position etc. of the signal frequency of such as pumping signal radiating circuit, rotation or translation motor.By the software that loads in the terminal computer work process having coordinated whole device with EP2C8Q208C8N type FPGA.

C8051F340 type single-chip microcomputer is interconnected by 8 bit data bus and EP2C8Q208C8N type FPGA, and C8051F340 type single-chip microcomputer is also interconnected by usb bus and terminal computer.Terminal computer is loaded with program, comprises: to the program of C8051F340 type single-chip microcomputer sending controling instruction, reception process program and biological tissue's electromagnetic parameter image reconstruction module of the data that C8051F340 type single-chip microcomputer is uploaded.

Open oscillating circuit 8, for accumulating the time that electromagnetic wave is propagated in biological tissues by repeatedly to vibrate, comprising: pumping signal radiating circuit 8-1, monostable trigger control circuit 8-2, timing circuit 8-3, delay circuit 8-4, AGC-shaping circuit 8-5 and signal conditioning circuit 8-6;

Pumping signal radiating circuit as shown in Figure 2, is made up of DDS (Direct frequency synthesizer) circuit, low-pass filter circuit 8-1-1, amplification shift circuit 8-1-2 and power amplification circuit; In present embodiment, the model of the DDS circuit adopted is AD9851BRS, the low-pass filter circuit adopted is the passive Low-pass Elliptic Filter of 70MHz be made up of electric capacity and inductance, the amplification shift circuit adopted is in series by two AD8099ARD chips and 1 AD8055ARZ chip to form, and the model of the power amplification circuit of employing is AD815AYS; The D0-D7 foot of AD9851BRS type DDS circuit is connected with the DDS_D0-DDS_D7 foot of EP2C8Q208C8N type FPGA respectively, and the W_CLK foot of AD9851BRS type DDS circuit, FQ_UD foot and RESET foot are connected to control by it with the DDS_WCLK foot of EP2C8Q208C8N type FPGA, DDS_FQUK foot with DDS_RESET foot respectively; DDS circuit output end, namely IOUT foot, VINN foot and IOUTB foot are connected respectively to three of low-pass filter circuit input in parallel; Low-pass filter circuit outfan is connected to the input amplifying shift circuit, i.e. the input of first AD8099ARD chip; The outfan (i.e. the outfan of AD8055ARZ chip) amplifying shift circuit connects the input of AD815AYS type power amplification circuit, and the output end vo end of AD815AYS type power amplification circuit connects transmitting coil.

Signal conditioning circuit as shown in Figure 3, turns single-end circuit 8-6-4 by input protection circuit 8-6-1, differential low-pass wave circuit 8-6-2, differential amplifier circuit 8-6-3 and difference in series in order.In present embodiment, the cache switching diodes parallel connection that input protection circuit is 1N4148 by 4 models is formed, and the model of differential filtering circuit and differential amplifier circuit is all AD8139ARD chips, and what difference turned single-end circuit employing is AD8055ARZ chip.The two ends of receiving coil are directly connected on two inputs of input protection circuit, then, the signal that receiving coil receives via the input of access differential low-pass filter circuit after input protection circuit, differential low-pass wave circuit to received signal in high-frequency noise carry out filtering process; Differential amplifier circuit amplitude is to received signal amplified; Difference turns single-end circuit and differential signal is converted to single-ended signal, eliminates common mode disturbances simultaneously.

As shown in Figure 4, the high-speed comparator being ADCMP601 by the operational amplifier that model is the programmable gain amplifier of AD8367ARU, model is the detection chip of AD8362ARU, model is AD820ARZ and model is formed AGC-shaping circuit.As the input V of the AD8367ARU programmable gain amplifier of AGC-shaping circuit input _inthe outfan of end connection signal modulate circuit, namely difference turns the outfan V of single-end circuit _outend; The outfan VOUT end of AD8367ARU programmable gain amplifier is connected to the input INPUT end of AD8362ARU detection chip and the input of ADCMP601 high-speed comparator simultaneously; The outfan VOUT end of AD8362ARU detection chip is connected to the input of AD820ARZ operational amplifier; The outfan of AD820ARZ operational amplifier is connected to the gain control input of AD8367ARU programmable gain amplifier.Input signal exports after AD8367ARU programmable gain amplifier amplifies, AD8362ARU detection chip carries out detection to output signal, detection exports the gain size that gain control making foot that direct current signal feeds back to AD8367ARU programmable gain amplifier after AD820ARZ operational amplifier amplifies carrys out Dynamic controlling AD8367ARU programmable gain amplifier, thus realize automatic growth control, namely automatic gain control, AGC.The output signal signal that receiving coil receives after ADCMP601 high-speed comparator is shaped to rectangular pulse signal.

Due to signal spread speed in circuit quickly, if do not controlled to cause the concussion frequency of open oscillating circuit very high, each control assembly in device and the response speed of timing piece just quickly just must can make whole device steady operation.For addressing this problem, after AGC-shaping circuit, devise a delay circuit.In present embodiment, delay circuit as shown in Figure 5, adopt the delay chip of two panels different delayed time scope in series, wherein the model of a slice delay chip is DS1023, the model of another sheet delay chip is MC10EP195, so just can realize the delays time to control of large scale and high accuracy, in present embodiment, between two panels delay chip, also be in series with the electrical level transferring chip that model is MC100ELT20.The output end vo ut of the input connection AGC-shaping circuit of DS1023 delay chip holds, then the signal that DS1023 delay chip exports accesses the input of MC10EP195 delay chip after level conversion is PECL level by MC100ELT20 electrical level transferring chip; The control of two delay chips is completed by FPGA and shift register, shift register adopt three models be SN74AHC595 shift register cascade form, for the serial control signal of FPGA is converted to parallel signal export.The DELAY_DLLE foot of EP2C8Q208C8N type FPGA connects the DELLE foot of DS1023 delay chip, the DELAY_LEN foot of EP2C8Q208C8N type FPGA connects the LEN foot of MC10EP195 delay chip, the DELAY_DATA foot of EP2C8Q208C8N type FPGA connects the DATA foot of first SN74AHC595 shift register, three SN74AHC595 shift registers are cascaded up by the connection of QH foot and DATA foot, the DELAY_RCLK foot of EP2C8Q208C8N type FPGA is all connected with the RCLK foot of three SN74AHC595 shift registers, the DELAY_SRCLK foot of EP2C8Q208C8N type FPGA is all connected with the SRCLK foot of three SN74AHC595 shift registers.

In present embodiment, the model of the monostable trigger control circuit adopted is SN54221, as shown in Figure 6, the outfan of delay circuit, namely the output Vout of MC10EP195 delay chip holds by a model is that SN74AUC1G32's or door input Vin holds the B foot connecting SN54221 type stable state trigger control circuit, should or another input of door connect the PULSE_ST foot of EP2C8Q208C8N type FPGA; What SN54221 type monostable flipflop output signal was SN74AUC08 through four models goes out three tunnels identical signal SIG1, SIG2, SIG3 with door leaf, SIG1 signal is connected to the OE end of the AD815AYS type power amplification circuit in pumping signal radiating circuit, the high-frequency count module that SIG3 signal inputs to EP2C8Q208C8N type FPGA carries out pulse number counting, namely access the PULSE_CNT end of EP2C8Q208C8N type FPGA, SIG2 signal inputs to the either end in S1 and S2 of timing circuit.

Timing circuit as shown in Figure 7, is that the d type flip flop that SN74AUC1G32's or door, model to be the high-frequency clock generator of MAX2870 and model be SN74AUC1G74's rising edge triggers is formed by model.Present embodiment adopts MAX2870 type high-frequency clock generator to produce high frequency clock signal to carry out timing just, the control signal input of MAX2870 type high-frequency clock generator, namely LD foot, MUX_OUT foot, CLK foot, DATA foot, LE foot and CE foot are connected to control by it with the TIMER_LD foot of EP2C8Q208C8N type FPGA, IMER_MO foot, IMER_CLK foot, IMER_DATA foot, IMER_LE foot with IMER_CE foot respectively.SN74AUC1G32 type or door two inputs as two inputs of timing module, the outfan of SN74AUC1G32 type or door connects the input of SN74AUC1G74 type d type flip flop, one of them of two inputs of such timing module receives pulse signal all can make the outfan of SN74AUC1G74 type d type flip flop overturn, thus control MAX2870 type high-frequency clock generator whether clock signal carries out timing.

The work schedule of the open oscillating circuit of present embodiment is such: after sending pulse control signal from monostable trigger control circuit, is T1 through pumping signal radiating circuit to producing actual time of excitation electromagnetic field.Signal electronic circuit response time in signal conditioning circuit, AGC-shaping circuit, monostable trigger control circuit and pumping signal radiating circuit is respectively T2, T3, T5, T6, and circuit determines that rear T2, T3, T5, T6 are changeless.The delay time of delay circuit setting is T4.So, the cycle of oscillation of described open oscillating circuit is T=T1+T2+T3+T4+T5+T6, wherein, T2, T3, T4, T5, T6 are constant, are the system intrinsic time, for different biological tissues, T1 is only had to be different, T4 time longer cycle of oscillation, T was also longer simultaneously, and the frequency of oscillation of whole open oscillating circuit is also less, so just can reach the object of the frequency of oscillation controlling described open oscillating circuit by changing T4.

As shown in Figure 8, electromagnetic radiation coil 1, electromagnetic wave receiving coil 2 are 1.5cm, the high coil fixed support 13 made for the acrylic pipe of 5cm respectively by diameter, be fixed in the two-arm of U-shaped arm 3, the relative position of two coils immobilizes, and the axis of electromagnetic radiation coil 1 and electromagnetic wave receiving coil 2 in the same horizontal line; The one end at the transmitting coil place of U-shaped arm 3 is connected (as long as translation motor 5-2 to be connected with U-shaped arm 3 and can move horizontally by smooth drive U-shaped arm 3 by the second leading screw 12 with the output shaft end of translation motor 5-2, link position is without particular/special requirement), namely drive U-shaped arm straps to move above-mentioned two coils by translation motor 5-2 and do translational motion;

Diameter is that the upper end face of the cylinder object stage 4 of 20cm places biological tissue 9 to be measured, object stage 4 is placed in the inner chamber of U-shaped arm 3, and leave certain gap between the two-arm of U-shaped arm 3, the setting in this gap is the rotation in order to make U-shaped arm 3 not affect object stage 4; Object stage 4 is connected by the output shaft end of leading screw 11 with rotating stepper motor 5-1, namely drives the biological tissue to be measured that object stage is placed to be rotated by rotating stepper motor 5-1 driving objective table 4; Because the velocity of rotation of object stage is very slow, when object stage 4 rotates, biological tissue 9 can not be moved.

Concrete translating step and the described object stage rotary step of described U-shaped arm can adjust according to the geometry of biological tissue 9.

In present embodiment, the rotating stepper motor drive circuit of employing is peaceful, and to move the structure of stepper motor driving circuit identical, and what all adopt is THB6128 stepper motor driver chip, as shown in Figure 9.The input P1 end of THB6128 stepper motor driver chip is connected with FPGA, and outfan J1 end is then connected with the power access end of motor.

Present embodiment, before experiment starts, the thick iron sheet of 0.5mm is adopted to make closed screening can 10, biological tissue 9 to be measured, object stage 4, rotating stepper motor 5-1, U-shaped arm 3, electromagnetic radiation coil 1, the peaceful motor 5-2 that moves of electromagnetic wave receiving coil 2 are included in wherein, electromagnetic shielding is carried out to them.

The measuring device of the propagation velocity of electromagnetic wave of the biological tissue described in following employing present embodiment, measures the method for electromagnetic wave spread speed in biological tissues, as shown in Figure 10, comprises the steps:

Step 1: the initialization of the measuring device of the propagation velocity of electromagnetic wave of biological tissue 9;

Step 1.1: send initialization directive from terminal computer, and send this instruction to FPGA by single-chip microcomputer;

Step 1.2: after receiving initialization directive, EP2C8Q208C8N type FPGA controls pumping signal radiating circuit, monostable trigger control circuit, timing circuit and delay circuit and completes initial work;

Step 1.2.1:EP2C8Q208C8N type FPGA transmits control signal to pumping signal radiating circuit, the signal tranmitting frequency of setting pumping signal radiating circuit;

Step 1.2.2:EP2C8Q208C8N type FPGA sends reset signal to monostable trigger control circuit, and monostable trigger control circuit is resetted;

Step 1.2.3:EP2C8Q208C8N type FPGA transmits control signal to timing circuit, first makes timing circuit reset, and then arranges the output clock frequency of timing circuit;

Step 1.2.4:EP2C8Q208C8N type FPGA transmits control signal to delay circuit, arranges the delay time of delay circuit;

Step 2: the electromagnetic wave propagation measure of time of biological tissue 9;

Tomoscan method is adopted to carry out the electromagnetic wave propagation measure of time of biological tissue 9, as shown in figure 11.

Step 2.1: at initial position, namely object stage 4 rotates, and U-shaped arm 3 does not carry out translation, carries out the measurement of the electromagnetic wave propagation time of biological tissue 9;

Step 2.1.1: terminal computer sends and starts measurement instruction and send this instruction to EP2C8Q208C8N type FPGA by C8051F340 type single-chip microcomputer;

Step 2.1.2:EP2C8Q208C8N type FPGA sends one and starts the pulse signal of measurement and be sent to monostable trigger control circuit;

Step 2.1.3: monostable trigger control circuit is triggered after receiving pulse signal, produces the pulse signal of three tunnel 50 nanosecond pulse width (pulse signal width can adjust according to frequency of oscillation); Wherein a road pulse signal is sent to the high speed counting module in EP2C8Q208C8N type FPGA, for recording impulse number of times; Another road pulse signal sends to timing circuit, starts timing for controlling timing circuit; 3rd road pulse signal sends to pumping signal radiating circuit;

Step 2.1.4: after receiving pulse signal, pumping signal radiating circuit drives electromagnetic radiation coil 1 to generate electromagnetic waves; This electromagnetic wave, through biological tissue 9, is sent to signal conditioning circuit by electromagnetic wave receiving coil 2;

Step 2.1.5: signal conditioning circuit is sent to AGC-shaping circuit after carrying out filter amplifying processing to the electromagnetic wave received;

Step 2.1.6: receive the electromagnetic wave signal after filter and amplification, AGC-shaping circuit carries out automatic range-adjusting to it and is sent to delay circuit after being shaped as rectangular pulse signal;

Step 2.1.7: after delay circuit receives rectangular pulse signal, the time delayed signal of generation imports timing circuit and monostable trigger control circuit into simultaneously;

Step 2.1.8: after receiving time delayed signal, timing circuit stops timing, single-shot trigger circuit is again triggered and (is triggered different from first time simultaneously, open oscillating circuit only has primary startup ranging pulse signal to be that EP2C8Q208C8N type FPGA sends, each cycle of oscillation afterwards, EP2C8Q208C8N type FPGA no longer sends and starts ranging pulse signal);

Step 2.1.9: repeated execution of steps 2.1.3 to 2.1.8, until after the count value of EP2C8Q208C8N type FPGA high speed counting module reaches the maximum count value (maximum needs according to biological tissue 9 and the practical situation of frequency of oscillation and determines) of in advance setting, EP2C8Q208C8N type FPGA sends reset enable signal monostable trigger control circuit and resets, and namely open oscillating circuit stops oscillation;

Step 2.1.10: the time value that timer when stopping oscillation according to maximum count value and open oscillating circuit provides, EP2C8Q208C8N type FPGA calculate the electromagnetic wave propagation time of biological tissue, are designated as D ₀₀;

The computational methods of electromagnetic wave propagation time are the maximum count value of time value divided by correspondence of timer transmission;

Step 2.2: keep object stage 4 motionless, U-shaped arm 3 carries out translational motion, measures the electromagnetic wave propagation time of biological tissue 9;

EP2C8Q208C8N type FPGA drives translation motor 5-2 running by translation motor drive circuit, and U-shaped arm 3 is moved horizontally according to pre-determined step-length; U-shaped arm 3 records the electromagnetic wave propagation time of biological tissue 9 after often moving to a new position according to step 2.1.1 to step 2.1.10; After U-shaped arm 3 moves n time, record the electromagnetic wave propagation time data of one group of biological tissue 9, be designated as D respectively ₀₁, D ₀₂..., D _0n;

Step 2.3: object stage 4 rotates, and U-shaped arm 3 translation, measure the electromagnetic wave propagation time of biological tissue 9;

EP2C8Q208C8N type FPGA drives rotating stepper motor 5-1 to rotate by electric rotating machine drive circuit, object stage 4 is rotated according to pre-determined step-length, after object stage 4 often rotates to a new position, repeated execution of steps 2.1 to step 2.2, what record object stage 4 once rotates the electromagnetic wave propagation time data that the motionless and U-shaped arm 3 of corresponding U-shaped arm 3 moves n time; Then by repeated execution of steps 2.1 to step 2.2, after object stage 4 often rotates to a new position, can obtain one group of data, then object stage 4 completes 360 degree of rotations, number of revolutions is after m, and the data set of the electromagnetic wave propagation time of the biological tissue 9 obtained is:

$D=\left[\begin{array}{ccccc}{D}_{00}& D_{01}& D_{02}& ...& D_{0n}\\ D_{10}& D_{11}& D_{12}& ...& D_{1n}\\ D_{20}& D_{21}& D_{22}& ...& D_{2n}\\ ...& ...& ...& ...& ...\\ D_{m0}& D_{m1}& D_{m2}& ...& D_{\mathrm{mn}}\end{array}\right]$

The advantage of this method is the measurement data that can obtain the whole 360 degree of scopes of described biological tissue 9 easily, can cover the measuring range of whole biological tissue 9 on every once position simultaneously.

In sum, what be appreciated that out that the present invention adopts is tomoscan measurement method, and behind U-shaped arm 3 or the every new position of object stage 4, the propagation velocity of electromagnetic wave that will perform a biological tissue 9 is measured.Such as, when rotary step r is 10 degree, translating step l is 2cm, if the Breadth Maximum w of biological tissue 9 is 20cm, then means that the number of times that whole measurement needs carry out is:

Namely rotate 10 degree after every 10 translations, each translation or perform once the measurement of described propagation velocity of electromagnetic wave after rotating to a new position, obtain 350 independent measurement data.And these 350 independent measurement data only use a transmitting coil and a receiving coil to adopt the method for tomoscan to obtain in the present invention.That is, the present invention can increase independently measurement data when not needing many transmitting coils and receiving coil, impact simultaneously between each measurement data reaches minimum, also there will not be the situation existing and interfere with each other between the situation lower coil of multiple coil, the data obtained like this are more stable.Thus the measuring device of this biological tissue propagation velocity of electromagnetic wave proposed based on the present invention and method, high-resolution biological tissue dielectric constant distributed image can be obtained by simple Mechanical course operation.

The data of above-mentioned data centralization are uploaded to terminal computer by single-chip microcomputer by step 3:EP2C8Q208C8N type FPGA in real time one by one, terminal computer is according to the distance between electromagnetic radiation coil 1 and electromagnetic wave receiving coil 2, and the propagation velocity of electromagnetic wave data set utilizing speed formula to calculate each position of above-mentioned data corresponding biological tissue 9 is:

$V=\left[\begin{array}{ccccc}{V}_{00}& V_{01}& V_{02}& ...& V_{0n}\\ V_{10}& V_{11}& V_{12}& ...& V_{1n}\\ V_{20}& V_{21}& V_{22}& ...& V_{2n}\\ ...& ...& ...& ...& ...\\ V_{m0}& V_{m1}& V_{m2}& ...& V_{\mathrm{mn}}\end{array}\right]$

Step 4: terminal computer starts image reconstruction program, the data set V utilizing step 3 to obtain, adopts regularization Gauss-Newton algorithm for reconstructing (NOSER) to carry out image reconstruction to biological tissue 9, obtains the reconstruction image of biological tissue 9;

Image reconstruction is from maxwell equation group, and according to electromagnetic field wave equation, assuming that biological tissue is even and isotropic, namely pcrmeability μ and DIELECTRIC CONSTANT ε be not with change in location, also do not change with the direction of field.Multiple transmission coefficient k can be expressed as k=α+j β, and wherein α is called as electromagnetic attenuation quotient, can describe the attenuation degree of plane wave per unit distance, and its expression formula is formula (1):

$\mathrm{\α}=\mathrm{\ω}\sqrt{\frac{{\mathrm{\μ\ϵ}}^{\′}}{2}}{(\sqrt{1+{\left(\frac{{\mathrm{\ϵ}}^{\′\′}}{{\mathrm{\ϵ}}^{\′}}\right)}^2}-1)}^2---\left(1\right)$

β is electromagnetic phase coefficient, and represent that per unit is apart from delayed phase place, its expression formula is formula (2):

$\mathrm{\β}=\mathrm{\ω}\sqrt{\frac{{\mathrm{\μ\ϵ}}^{\′}}{2}}{(\sqrt{1+{\left(\frac{{\mathrm{\ϵ}}^{\′\′}}{{\mathrm{\ϵ}}^{\′}}\right)}^2}+1)}^2---\left(2\right)$

In formula (1) and formula (2), the real part that ε ' is complex dielectric permittivity, if the imaginary part ε of dielectric constant, and " exist, then α is not equal to zero, thus there is loss.ε "/ε ' be referred to as loss angle tangent.In desirable medium, ε "=0, then there is ε=ε '.Thus obtain α=0, have

$v=\frac{\mathrm{\ω}}{\mathrm{\β}}=\frac{1}{\sqrt{{\mathrm{\μ\ϵ}}^{\′}}}---\left(3\right)$

$\mathrm{\λ}=\frac{2\mathrm{\π}}{\mathrm{\β}}=\frac{1}{f\sqrt{{\mathrm{\μ\ϵ}}^{\′}}}---\left(4\right)$

From formula (3) and formula (4), electromagnetic wave spread speed is in biological tissues determined by its dielectric constant and pcrmeability.Wherein, in the pcrmeability of biological tissue and vacuum, pcrmeability is very close, therefore electromagnetic wave speed in biological tissues depends primarily on its dielectric constant.Therefore, theoretically prove can by measure electromagnetic wave in biological tissues spread speed rebuild biological tissue's dielectric constant image.

According to actual size and the physical property of transmitting coil 1 and receiving coil 2 and biological tissue 9 to be measured, Finite Element Method is adopted to set up the phantom of transmitting coil 1, receiving coil 2 and biological tissue 9 to be measured, simultaneously, according to the measuring method in step 2.2 and step 2.3, in phantom, the position relationship of transmitting coil 1, receiving coil 2 and biological tissue to be measured 9 is arranged;

According to the measuring method in step 2.2 and step 2.3 and phantom, adopt the measuring process of Finite Element Method Simulation electromagnetic wave spread speed in biological tissues, utilize Finite Element Method to calculate in the present invention the sensitivity matrix measuring electromagnetic wave spread speed in biological tissues simultaneously.

Equally, the propagation velocity of electromagnetic wave that the corresponding finite element solving in each position of biological tissue 9 calculates, the propagation velocity of electromagnetic wave data set obtaining emulating the biological tissue 9 solved is:

$V^{\′}=\left[\begin{array}{ccccc}{V}_{00}^{\′}& V_{01}^{\′}& V_{02}^{\′}& ...& V_{0n}^{\′}\\ V_{10}^{\′}& V_{11}^{\′}& V_{12}^{\′}& ...& V_{1n}^{\′}\\ V_{20}^{\′}& V_{21}^{\′}& V_{22}^{\′}& ...& V_{2n}^{\′}\\ ...& ...& ...& ...& ...\\ V_{m0}^{\′}& V_{m1}^{\′}& V_{m2}^{\′}& ...& V_{\mathrm{mn}}^{\′}\end{array}\right]$

Present embodiment, in biological tissue's electromagnetic parameter image reconstruction module, adopts regularization Gauss-Newton algorithm for reconstructing to rebuild the image of biological tissue 9 dielectric constant.The cost functional that one has quadratic sum form is constructed by the difference of data set V and data set V '.

Pass between the discrete DIELECTRIC CONSTANT ε of measuring speed v and tested biological tissue 9 is,

v＝Ψ(ε) (5)

Structure L ₂norm:

$Q={\left|\right|v-\mathrm{\ψ}\left(\mathrm{\ϵ}\right)\left|\right|}_2^2---\left(6\right)$

Solve ε ^kmake Q reach minima, first derivative asked to Q, and make it be 0:

Q′＝[Ψ′(ε)] ^T[v-Ψ(ε)]＝0 (7)

Make Q ' at ε ^kplace makes Taylor and launches, and omits high-order term, only gets linear term, then have:

Q′＝Q′(ε ^(k))+Q″(ε ^(k))Δε ^(k) (8)

Q ' is Hessian matrix, to formula (7) differentiate, is similar to and tries to achieve:

Q″＝-[Ψ′(ε)] ^TΨ′(ε) (9)

Formula (7) and formula (8) are substituted into formula (9), arrange:

Δσ ^(k)＝{[Ψ′(ε ^(k))] ^TΨ′(ε ^(k))}·[Ψ′(ε ^(k))] ^T·(v-Ψ(ε ^(k))) (10)

Wherein Ψ ' (ε ^(k)) be sensitivity matrix, represent with S, formula (10) is reduced to:

Δε ^(k)＝(S ^TS) ^-1S ^T·(v-Ψ(ε ^(k))) (11)

Tikhonov regularization correction is carried out to formula (11), Algorithm Convergence and stability can be improved.

Getting regularization factors λ > 0, I is unit matrix:

cond(S ^TS+λI) ₂＜cond(S ^TS) ₂ (12)

Introduce norm function reconstruct norm L ₂:

$Q={\left|\right|v-\mathrm{\Ψ}\left(\mathrm{\ϵ}\right)\left|\right|}_2^2+\mathrm{\λ}{\left|\right|\mathrm{\Δ\ϵ}\left|\right|}_2^2---\left(13\right)$

Be Taylor to Ψ to launch to omit higher order term substitution formula (13), obtaining cost functional is formula (14):

$Q={\left|\right|S^T(v-\mathrm{\Ψ}\left(\mathrm{\ϵ}\right))-\mathrm{S\Δ\ϵ}\left|\right|}_2^2+\mathrm{\λ}{\left|\right|\mathrm{\Δ\ϵ}\left|\right|}_2^2---\left(14\right)$

The minimum of modus ponens (14), obtains equation:

(S ^TS+λI)Δε ^(k)＝S ^T(v-Ψ(ε ^(k))) (15)

Solve formula (15) can obtain:

Δε ^(k)＝(S ^TS+λI) ^-1S ^T(v-Ψ(ε ^(k))) (16)

And then have:

ε ^(k+1)＝ε ^(k)+Δε ^(k) (17)

According to the propagation velocity of electromagnetic wave data set V ' of direct problem finite element numerical model solution, give reconstruction regions and often put an initial value 1, then interative computation is carried out according to formula (17), FEM calculation value by the velocity of electromagnetic wave of the measured value in step 2.2 and step 2.3 and step 4 compares, and carries out interative computation in conjunction with Regularization Technique.In each step interative computation, result is revised, new interative computation is carried out again in the new result revised, also constantly recalculating sensitivity matrix by continuous iteration makes cost functional formula (14) minimum, thus obtain dielectric constant distributed image, as shown in figure 12 for the present invention is the beaker imaging results of 7cm to a diameter, be placed with the sodium chloride solution of concentration 1% in beaker for imitated biological tissue, beaker is placed on object stage centre position.In sum, can learn, utilize electromagnetic wave spread speed in biological tissues can rebuild biological tissue's dielectric constant image.

Although the foregoing describe the specific embodiment of the present invention, the those skilled in the art in this area should be appreciated that these only illustrate, can make various changes or modifications, and do not deviate from principle of the present invention and essence to these embodiments.Scope of the present invention is only defined by the appended claims.

Claims (8)

1. based on biological tissue's electromagnetic parameter imaging device of propagation velocity of electromagnetic wave, it is characterized in that: comprising: electromagnetic radiation coil, electromagnetic wave receiving coil, U-shaped arm, object stage, electric motor units, electric-motor drive unit, control unit and open oscillating circuit;

Described control unit is formed primarily of FPGA, single-chip microcomputer and terminal computer; Described single-chip microcomputer and FPGA interconnect, and single-chip microcomputer also interconnects with terminal computer simultaneously;

Described open oscillating circuit is used for accumulating the time that electromagnetic wave is propagated in biological tissues by repeatedly vibrating, and it comprises: monostable trigger control circuit, pumping signal radiating circuit, signal conditioning circuit, AGC-shaping circuit, delay circuit and timing circuit;

Described monostable trigger control circuit and FPGA interconnect, an input of monostable trigger control circuit connects an outfan of delay circuit simultaneously, an outfan of monostable trigger control circuit connects the input of pumping signal radiating circuit, and another outfan of monostable trigger control circuit connects an input of timing circuit; The outfan of described pumping signal radiating circuit connects electromagnetic radiation coil, and pumping signal radiating circuit connects FPGA by data/address bus simultaneously, the data that unidirectional reception FPGA sends; Another input of described timing circuit connects another outfan of delay circuit, and timing circuit also interconnects with FPGA simultaneously; The input of described delay circuit connects the outfan of AGC-shaping circuit; The outfan of the input connection signal modulate circuit of described AGC-shaping circuit; The input of described signal conditioning circuit connects electromagnetic wave receiving coil;

Described electromagnetic radiation coil is used under the driving of pumping signal radiating circuit, produce the electromagnetic wave that can pass biological tissue;

Described electromagnetic wave receiving coil is for receiving the electromagnetic wave through biological tissue;

Described electromagnetic radiation coil, electromagnetic wave receiving coil are separately fixed in the two-arm of U-shaped arm, and the axis of electromagnetic radiation coil and electromagnetic wave receiving coil in the same horizontal line;

Described object stage, for placing biological tissue to be measured, is placed in the inner chamber of U-shaped arm, and and leave corresponding gap between the two-arm of U-shaped arm;

Described electric motor units is for driving U-shaped arm to carry out translational motion and object stage is rotated, and it comprises: translation motor carries out translational motion for driving U-shaped arm; Rotating stepper motor is used for driving objective table and is rotated;

Described electric-motor drive unit is used for the operation of motor in drive motor units, and it comprises: translation stepper motor driving circuit is the drive circuit of described translation motor, for driving the translation operation of translation motor; Rotating stepper motor drive circuit is the drive circuit of described rotating stepper motor, for driving the rotating operation of rotating stepper motor;

U-shaped arm is connected with the output shaft end of translation motor, the power access end of described translation motor connects the outfan of translation stepper motor driving circuit, the input of described translation stepper motor driving circuit connects FPGA by control bus, receives the control command signal that FPGA sends;

Described object stage is connected with rotating stepper motor output shaft end; The power access end of described rotating stepper motor connects the outfan of rotating stepper motor drive circuit, and the input of described rotating stepper motor drive circuit connects FPGA by control bus, receives the control command signal that FPGA sends;

Also being provided with biological tissue's electromagnetic parameter image reconstruction module in described terminal computer, for carrying out image reconstruction to biological tissue, obtaining the reconstruction image of biological tissue.

2. the biological tissue's electromagnetic parameter imaging device based on propagation velocity of electromagnetic wave according to claim 1, it is characterized in that: adopt the thick iron sheet of 0.5mm to make closed screening can, biological tissue to be measured, object stage, rotating stepper motor, U-shaped arm, electromagnetic radiation coil, the peaceful motor that moves of electromagnetic wave receiving coil are included in wherein by this screening can, carry out electromagnetic shielding to them.

3. the biological tissue's electromagnetic parameter imaging device based on propagation velocity of electromagnetic wave according to claim 1, it is characterized in that: when described object stage is placed in the inner chamber of U-shaped arm, the gap between itself and the two-arm of U-shaped arm does not affect object stage with U-shaped arm and rotates as principle adjusts.

4. the biological tissue's electromagnetic parameter imaging device based on propagation velocity of electromagnetic wave according to claim 1, it is characterized in that: object stage is cylinder, on it, end face places biological tissue to be measured.

5. the biological tissue's electromagnetic parameter imaging device based on propagation velocity of electromagnetic wave according to claim 1, is characterized in that: object stage and U-shaped arm all by leading screw respectively the output shaft end that move motor peaceful to the output shaft end of rotating stepper motor be connected.

6. adopt biological tissue's electromagnetic parameter formation method of the biological tissue's electromagnetic parameter imaging device based on propagation velocity of electromagnetic wave according to claim 1, it is characterized in that: comprise the steps:

Step 1: device initializes;

Step 2: the electromagnetic wave propagation time of measuring biological tissue, obtain the electromagnetic wave propagation time data collection D of biological tissue;

The electromagnetic wave propagation time of biological tissue is uploaded to terminal computer by single-chip microcomputer by step 3:FPGA in real time, terminal computer is according to the distance between electromagnetic radiation coil and electromagnetic wave receiving coil, speed formula is utilized to calculate the propagation velocity of electromagnetic wave of each position of biological tissue, the propagation velocity of electromagnetic wave data set V obtained, as follows:

$V=\left[\begin{array}{ccccc}{V}_{00}& V_{01}& V_{02}& ...& V_{0n}\\ V_{10}& V_{11}& V_{12}& ...& V_{1n}\\ V_{20}& V_{21}& V_{22}& ...& V_{2n}\\ ...& ...& ...& ...& ...\\ V_{m0}& V_{m1}& V_{m2}& ...& V_{\mathrm{mn}}\end{array}\right]$

Step 4: the propagation velocity of electromagnetic wave data set V utilizing step 3 to obtain, adopts regularization Gauss-Newton algorithm for reconstructing to carry out image reconstruction to biological tissue, obtains the reconstruction image of biological tissue.

7. biological tissue according to claim 6 electromagnetic parameter formation method, is characterized in that: the device initialization procedure in described step 1, comprises the steps:

Step 1.1: send initialization directive from terminal computer, and send this instruction to FPGA by single-chip microcomputer;

Step 1.2: after receiving initialization directive, FPGA controls pumping signal radiating circuit, monostable trigger control circuit, timing circuit and delay circuit and completes initial work;

Step 1.2.1:FPGA transmits control signal to pumping signal radiating circuit, the signal tranmitting frequency of setting pumping signal radiating circuit;

Step 1.2.2:FPGA sends reset signal to monostable trigger control circuit, and monostable trigger control circuit is resetted;

Step 1.2.3:FPGA transmits control signal to timing circuit, first makes timing circuit reset, and then arranges the output clock frequency of timing circuit;

Step 1.2.4:FPGA transmits control signal to delay circuit, arranges the delay time of delay circuit.

8. biological tissue according to claim 6 electromagnetic parameter formation method, is characterized in that, the electromagnetic wave propagation time of the measurement biological tissue in described step 2, obtains the electromagnetic wave propagation time data collection D of biological tissue, comprises the steps:

Step 2.1: at initial position, namely object stage rotates, and U-shaped arm does not carry out translation, carries out the measurement of the electromagnetic wave propagation time of biological tissue;

Step 2.1.1: terminal computer sends and starts measurement instruction and send this instruction to FPGA by single-chip microcomputer;

Step 2.1.2:FPGA sends one and starts the pulse signal of measurement and be sent to monostable trigger control circuit;

Step 2.1.3: monostable trigger control circuit is triggered after receiving pulse signal, produces three road pulse signals; Wherein a road pulse signal is sent to the high speed counting module in FPGA, for recording impulse number of times; Another road pulse signal sends to timing circuit, starts timing for controlling timing circuit; 3rd road pulse signal sends to pumping signal radiating circuit;

Step 2.1.4: after receiving pulse signal, pumping signal radiating circuit drives electromagnetic radiation coil generating electromagnetic ripple; This electromagnetic wave, through biological tissue, is sent to signal conditioning circuit by electromagnetic wave receiving coil;

Step 2.1.5: signal conditioning circuit is sent to AGC-shaping circuit after carrying out filter amplifying processing to the electromagnetic wave received;

Step 2.1.6: receive the electromagnetic wave signal after filter and amplification, AGC-shaping circuit carries out automatic range-adjusting to it and is sent to delay circuit after being shaped as rectangular pulse signal;

Step 2.1.7: after delay circuit receives rectangular pulse signal, the time delayed signal of generation imports timing circuit and monostable trigger control circuit into simultaneously;

Step 2.1.8: after receiving time delayed signal, timing circuit stops timing, and single-shot trigger circuit is triggered again simultaneously;

Step 2.1.9: repeated execution of steps 2.1.3 to 2.1.8, until after the count value of FPGA high speed counting module reaches the maximum count value of in advance setting, FPGA sends reset enable signal monostable trigger control circuit and resets, and namely open oscillating circuit stops oscillation;

Step 2.1.10: the time value that timer when stopping oscillation according to maximum count value and open oscillating circuit provides, FPGA calculate the electromagnetic wave propagation time of biological tissue, are designated as D ₀₀;

The computational methods of electromagnetic wave propagation time are the maximum count value of time value divided by correspondence of timer transmission;

Step 2.2: keep object stage motionless, U-shaped arm carries out translational motion, measures the electromagnetic wave propagation time of biological tissue;

FPGA drives the running of translation motor by translation motor drive circuit, and U-shaped arm is moved horizontally according to pre-determined step-length; U-shaped arm records the electromagnetic wave propagation time of biological tissue after often moving to a new position according to step 2.1.1 to step 2.1.10; After U-shaped arm moves n time, record the electromagnetic wave propagation time data of one group of biological tissue, be designated as D respectively ₀₁, D ₀₂..., D _0n;

Step 2.3: object stage rotates, and the translation of U-shaped arm, measure the electromagnetic wave propagation time of biological tissue;

FPGA drives rotating stepper motor to rotate by electric rotating machine drive circuit, object stage is rotated according to pre-determined step-length, after object stage often rotates to a new position, repeated execution of steps 2.1 to step 2.2, records the electromagnetic wave propagation time data once rotating motionless and U-shaped arm n the movement of corresponding U-shaped arm of object stage; Then by repeated execution of steps 2.1 to step 2.2, after object stage often rotates to a new position, one group of data can be obtained, then object stage completes 360 degree of rotations, number of revolutions is after m, the data set D of the electromagnetic wave propagation time of the biological tissue obtained, as follows:

$D=\left[\begin{array}{ccccc}{D}_{00}& D_{01}& D_{02}& ...& D_{0n}\\ D_{10}& D_{11}& D_{12}& ...& D_{1n}\\ D_{20}& D_{21}& D_{22}& ...& D_{2n}\\ ...& ...& ...& ...& ...\\ D_{m0}& D_{m1}& D_{m2}& ...& D_{\mathrm{mn}}\end{array}\right].$